#include <stdio.h>
int main(void)
{
    float mass_mol = 3.0e-23; // mass of water molecule in grams
    float mass_qt = 950; // mass of quart of water in grams
    float quarts;
    float molecules;
    
    printf("Enter the number of quarts of water: ");
    scanf("%f", & quarts);
    molecules = quarts * mass_qt / mass_mol;
    printf("%f quarts of water contain %e molecules.\n", quarts, molecules);

    return 0;
}